Outbreak of Imported Seventh Pandemic Vibrio cholerae O1 El Tor, Algeria, 2018

C holera, a life-threatening diarrheal disease, is caused by Vibrio cholerae O1, or more rarely O139, serogroup bacteria that produce cholera toxin (CTX) and induce rapid massive loss of body fluids (1).Cholera has been a serious public health problem since its introduction into Africa in 1970, during the seventh cholera pandemic (2).This pandemic, caused by the novel V. cholerae O1 lineage El Tor (seventh pandemic El Tor), began in Indonesia in 1961 (2,3).After 60 years, ≈2.9 million cholera cases and ≈95,000 deaths still occur annually (4,5).During 2009-2012, nearly 60% of global cholera cases and deaths occurred in sub-Saharan Africa, but North Africa was considered cholera-free (5).Algeria is a large country (2,381,741 km 2 ) in North Africa (6).The World Bank (https://www.world-bank.org)ranks Algeria as the third largest economy in the Middle East and North Africa region.In 2018, Algeria had ≈42.2 million inhabitants, ≈30.6 million of whom lived in urban areas (Macrotrends LLC, https://www.macrotrends.net).Algeria reported cholera cases to the World Health Organization from 1971 (1,332 cases, 110 deaths) through 1994 (118 cases, 4 deaths), with a peak in 1979 (2,513 cases, 94 deaths) (Global Health Observatory, https://www.who.int/data/gho)(Figure 1).After a lull of >20 years, on August 23, 2018, the country's ministry of health announced a cholera outbreak in north Algeria (7).During August 7-September 27, 2018, Algeria reported 291 suspected cholera cases, including 270 persons who were hospitalized, in 7 wilayas (provinces): 6 in north-central Algeria (Bouira, Blida, Algiers, Tipaza, Aïn Defla, and Médéa) and 1 in northwest Algeria (Oran).We used conventional microbiology and wholegenome sequencing to characterize virulence and antimicrobial resistance of clinical and environmental isolates collected during this outbreak.We also performed a phylogenomic analysis of >1,200 seventh pandemic El Tor genomes to determine whether the 2018 outbreak in Algeria was caused by a sublineage previously circulating in the country, a sublineage circulating in sub-Saharan Africa, or a new sublineage imported from elsewhere. The StudyThe Enterobacteria Laboratory of the Institut Pasteur d'Algérie performed microbial analyses for case confirmation (Appendix 1 Table 1, https:// wwwnc.cdc.gov/